NOTEBOOK: Sperry has grown into third TE spot

Kory Sperry knew it would take more than being able to catch for him to stay on the roster this year.

“You need to block and play special teams,” said Sperry, who gained about 20 pounds this offseason, much of it seemingly in his chest and shoulders. “Getting in the weight room, getting stronger is going to help you blocking. It’s about playing special teams, being aggressive, knowing your job.”

With the release of Kris Wilson, the third tight end spot behind Antonio Gates and Randy McMichael became much more likely to become Sperry’s.

Sperry, signed to the practice squad last September and then the 53-man roster in November, played in seven games (four catches, 73 yards) in 2010. Now up to about 265 pounds, he has seen more work the first week of camp than he did all last season. He has gotten the bulk of reps and been among Philip Rivers’ favorite targets, in large part because Gates and McMichael have not been practicing.

“Kory is one of our most improved players,” head coach Norv Turner said. “… He gives us that young Randy McMichael (type of) guy. He’s really improved as a blocker, and he’s always been a good receiver.”

Nuts ‘n’ Bolts

• Corey Liuget is hanging out in San Diego, looking for a place to live as he waits for his agent and the Chargers to reach an agreement. The sides spoke Tuesday but remain deadlocked over the number of guaranteed years. Liuget, the 18th pick, is one of three remaining unsigned first-round picks. Also unsigned are 17 and 19.

• Running back Ryan Mathews returned to practice after two days off. Due to what head coach Norv Turner called “soreness.” Left tackle Marcus McNeill, who rested a sore knee on Monday, also returned Tuesday . Receiver Vincent Brown, the team’s third-round pick, watched for the second day with a balky quadriceps.

• Second-round pick Marcus Gilchrist has already established himself as a special teams demon, and it is clear he is big in the Chargers’ plans on the cover and return teams, as well as on field goals. Said Gilchrist: “Anything on special teams has got Marcus Gilchrist’s name on it. It’s more opportunity to get on the field.”